Summary
Mammals like cows with multi-chambered stomachs that ferment cellulose with microbes.
In depth
Four chambers: rumen, reticulum, omasum and abomasum. Food is regurgitated and re-chewed (cud). Microbes ferment cellulose into volatile fatty acids, and microbial protein is digested later. They produce methane.
Rumination allows efficient digestion of plants. The animals absorb microbial products. Methane is a by-product.
Remember: only the abomasum resembles a true stomach.
Ruminants (cattle, sheep, goats, deer, giraffes) have a four-part stomach; the rumen holds around 100 litres in cattle and a dense community of bacteria, protozoa and fungi that ferment cellulose into volatile fatty acids (acetate, propionate, butyrate), which supply up to 70 percent of the animal's energy. Microbes themselves are digested in the abomasum, giving protein. Urea in saliva recycles nitrogen.
A cow produces up to 150 to 250 litres of methane daily, which has implications for climate, and feed additives and breeding aim to reduce this. Non-ruminant fermenters, such as horses and rabbits, use the caecum, and rabbits reingest soft faeces (caecotrophs). Ruminants allowed humans to use grass land that cannot grow crops.
Example: camels and llamas are pseudo-ruminants with three stomach chambers.
Frequently asked questions
What is Ruminants?
Mammals like cows with multi-chambered stomachs that ferment cellulose with microbes.
Which area of biology covers Ruminants, and how advanced is it?
Ruminants is one of the 53 topics in Zoology & Animal Diversity. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Animal Respiration, Metabolic Scaling, Digestive Strategies.
Can you give an example of Ruminants?
Cattle, sheep and deer.
What should I learn before Ruminants?
Work through the Beginner topics in Zoology & Animal Diversity first, such as Animal Kingdom, Vertebrates and Invertebrates, Sponges, then return to Ruminants. Intermediate topics assume the Beginner vocabulary.
What topics are related to Ruminants?
The closest topics to Ruminants are Animal Respiration, Metabolic Scaling, Digestive Strategies, Domestication Genetics. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Ruminants?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Ruminants. To practise the whole of Zoology & Animal Diversity, use the Zoology & Animal Diversity quiz.
How is Ruminants different from Animal Respiration?
Ruminants: Mammals like cows with multi-chambered stomachs that ferment cellulose with microbes. Animal Respiration: Gills, tracheae, book lungs and lungs exchange gases in aquatic and terrestrial animals. Read both side by side and note what each one explains.
How should I study Ruminants step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Animal Respiration and explain the difference aloud. Finally, take the Zoology & Animal Diversity quiz and come back to this page for any question you miss.